Performance of Vector Perturbation MU-MIMO Systems in a Composite Fading Channel

In this paper, we analyze the performance of vector perturbation (VP) precoded multiuser multiple-input multiple-output (MU-MIMO) systems in a composite fading channel including not only small-scale Rayleigh fading but also large-scale fading for getting useful conclusion in a more realistic scenario. Through the derivation of average power of sphere-encoded vectors, we obtained the closed-form expression of the sum rate tight lower bound of VP precoded MU-MIMO systems, which is a function of the number of transmit/receive antennas, transmit power and large-scale fading parameters. From the analytical expression of sum rate and error probability bounds, it is concluded that the performance of VP precoded MU-MIMO systems deteriorates severely when intended users experience very different large-scale fadings. Simulation results validate our analysis.